What is subclavian central venous access
Central venous access is required in a variety of clinical scenarios with the subclavian veins serving as the favored site in most cases.

Central venous access (CVC) is required in a variety of clinical scenarios, including hemodynamic monitoring, medication administration, and blood sample collection in intensive care settings.

The three veins in the body that are accessed during central venous cannulation are:

  1. The internal jugular
  2. The subclavian vein
  3. The femoral vein

The subclavian vein provides various advantages over other feasible locations for central venous access.

  • Subclavian central venous catheter placement is associated with a reduced rate of infection and thrombosis than internal jugular and femoral CVC placement.
  • When cervical collars obstruct access to the internal jugular vein, a subclavian line can be inserted swiftly using anatomic landmarks and is frequently used in trauma settings.

The risk of pneumothorax due to the anatomic proximity to the dome of the lung, which lies just superficial to the subclavian vein, is the disadvantage of subclavian access. Furthermore, in the event of an unintentional arterial puncture, the clavicle bone obstructs access to the subclavian artery, making effective vascular compression difficult.

How is subclavian central venous access performed?

A thorough working awareness of the target vascular anatomy, as well as flexibility in conducting the Seldinger method, is required for successful subclavian CVC implantation (an introduction of the catheter into a vessel over the guidewire, which is inserted through a thin-walled needle).

  • First, an 18-gauge thin-walled needle is used to cannulate the subclavian vein.
  • The needle is then threaded with a guidewire until it is properly positioned within the vessel. The needle is then removed, and a dilator is run over the wire to dilate the skin and soft tissue before passing the catheter over the wire until it is properly positioned within the vessel.
  • Finally, the guidewire is withdrawn, and the catheter is sutured to the skin.

The subclavian vein can be reached anatomically either a supraclavicular or infraclavicular approach.

2 approaches for subclavian central venous access

  1. Supraclavicular approach
    • To cannulate the vein via the supraclavicular technique, doctors position themselves at the head of the patient’s bed as if they were inserting an internal jugular line.
    • They visualize the vein with the probe above the clavicle. They may start with the internal jugular vein and work their way distally until it meets the subclavian vein.
    • Doctors place the needle tip of the probe in the center of the probe and penetrate the skin. They keep visualizing the needle tip until it enters the vessel.
    • Once the needle is in the lumen of the vessel, they insert the guidewire.
    • Doctors withdraw the needle and continue with the scalpel incision and dilatation before inserting the catheter over the guidewire.
    • When using the supraclavicular technique, doctors will always use the short axis view.
  2. Infraclavicular approach
    • Doctors position the probe in the infraclavicular fossa (if possible) under the collar bone and identify the vasculature 2 to 3 cm distal to where the subclavian vein flows below the clavicle.
    • When compared to the landmark technique, cannulation happens more laterally. Doctors get a long-axis picture of the axillary and distal subclavian veins.
    • To validate vein visualization, they use compressibility and pulse-wave Doppler (as opposed to the artery). They take note of the pleura of the lung beneath the arteries. Doctors then insert the needle near the midpoint of the probe's short footprint and keep the needle visible on the long axis as it approaches the vessel.
    • Once the needle is visible in the lumen, they insert the guidewire while using ultrasonography to monitor placement dynamically.
    • They insert the catheter over the guidewire after making an incision with a knife and dilating it.

There are multiple varieties of central venous catheter (CVC) kits that are widely accessible and are marketed by various vendors. CVCs can have a single lumen, two lumens, or three lumens. However, most healthcare staffs prefer using triple lumen CVC.

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6 indications for subclavian central venous access

  1. Central venous access for infusion of vasoactive medicines, total parenteral nutrition, high-dose potassium chloride, and other medications
  2. Hemorrhagic conditions requiring massive amounts of blood or blood products
  3. Central venous pressure measurement
  4. Where peripheral access is limited, regular blood draws are required
  5. Inadequate peripheral venous access
  6. Lack of peripheral venous access

3 contraindications for subclavian central venous access

  1. Severe coagulopathy is an absolute contraindication for subclavian central venous access
  2. Infected skin site
  3. Patients with higher risks for pneumothorax or inability to tolerate pneumothorax

5 possible risks due to subclavian central venous access

The likelihood of complications with subclavian central venous cannulation varies according to the doctor's experience and the circumstances (emergency vs. elective) under which the line is inserted. Nonetheless, it is always done after obtaining consent from a patient.

  1. Risk of arterial puncture (0.5 percent)
  2. Catheter malposition (9.3 percent)
  3. Hemo or pneumothorax (1.3 percent)
  4. Bloodstream infection (4 percent)
  5. Vessel occlusion or thrombosis (1.2 percent)

Ultrasound-guided subclavian vein access for central venous cannulation is a safe, effective, and efficient approach. The use of ultrasound can reduce the time to cannulation, as well as many of the predicted problems.

What is a subclavian vein?

The subclavian vein is a paired big vein that runs under the collarbone and anterior to the subclavian artery. The diameter of the vein is around the size of a small finger.

  • Each subclavian vein is a direct continuation of the axillary vein, which passes beneath the pectoralis minor muscle.
  • The subclavian vein receives venous blood from the internal and external jugular veins, as well as the dorsal scapular and anterior jugular veins.
  • The subclavian vein is the main vein that runs through the arm, shoulder, and neck. Because of the path, it follows on entering the thorax, its name implies "under the collarbone."

If a patient has lost a significant amount of blood or is difficult to cannulate, central venous access through major veins of the neck may be required. One of these is the subclavian vein.

The catheterization is done for two reasons.

  1. Long-term venous access with a few infections
  2. Central venous pressure monitoring

This entails inserting a large bore cannula, such as a Swan-Ganz catheter, into the subclavian vein to administer liquids and drugs.

5 common types of central venous access catheters

A central venous access catheter (CVAC) is a long-term intravenous that is implanted beneath the skin to allow doctors or nurses to collect blood or administer medication or nourishment in a straightforward, pain-free manner.

A central venous catheter (CVC) allows patients to avoid the discomfort of repeated needle sticks. The cannulation of a central venous catheter in interventional radiology is usually possible with moderate sedation and local anesthesia. 

  1. Tunneled small-bore or Hohn, Hickman, or Broviac catheters:
    • Infusions of antibiotics or other drugs, nutritional supplements, and chemotherapy treatments are common uses of these catheters.
    • These catheters may have retention cuffs to reduce infection risk and prevent unintentional removal.
    • Allows easy catheter removal depending on the projected duration of usage (typically months).
    • Some tunneled small-bore catheters can be utilized with a power injector to minimize the need for an intravenous catheter during a computed tomography (CT) scan or magnetic resonance imaging (MRI).
  2. Peripherally inserted central catheters (PICC) lines:
    • Usually inserted in the vein of the upper arm.
    • They are readily removed and are utilized when venous access is needed for several weeks to months.
    • Some PICC lines can be utilized with a power injector during a CT or MRI scan.
  3. Tunneled dual-lumen catheters: Implanted in patients requiring stem cell transplants or other purposes that need higher flow volumes than a small-bore catheter can provide.
  4. Tunneled dialysis catheters:
    • Usually used for patients who require hemodialysis.
    • These catheters are made to allow blood to flow quickly to and from the dialysis machine. The most common location for these is in the veins of the neck though other locations can be utilized if necessary.
    • Patients who require hemodialysis but do not have a working fistula or graft are fitted with tunneled dialysis catheters.
    • Interventional radiologists can employ techniques including angioplasty, stent implantation, and thrombolytic therapy to save a previously functional hemodialysis fistula or graft that is suffering poor flows or thrombosis.
  5. Implantable ports:
    • Mostly used for cancer chemotherapy or for people with disorders, such as cystic fibrosis, who require frequent venous access over a long period.
    • They are inserted and retrieved through a minor surgical incision and are completely hidden beneath the skin.
    • A special needle is used to get to them. These come with either a single lumen (the most popular) or two lumens.
    • Most of the ports can be used with a power injector for CT or MRI scans.

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When are central venous access catheters used?

Doctors often recommend CVACs for patients who regularly undergo:

  • Treatments with chemo
  • Antibiotic or other drug infusions
  • Infusions of nutritional supplements
  • Hemodialysis

Interventional radiologists can help remove a central venous access catheter when it is no longer needed or if a catheter-related infection develops. Peripherally inserted central catheters (PICC) lines and Hohn catheters can be easily removed at the bedside or in the clinic.

Other catheters may require sterile treatment, local anesthesia, and sedation to separate the cuff from the subcutaneous tissues. The removal of a port catheter necessitates a tiny incision.

Summary

Pneumothorax, vascular lacerations, acute thrombosis, catheter embolism, and notably sepsis are uncommon complications associated with subclavian venous catheterization. However, subclavian central venous catheterization is a safe way to establish venous access.

Larger research evaluating alternative venous approaches, particularly in terms of complications, is needed. Ultrasound can help enhance these benefits and reduce hazards.

  • With the use of ultrasound, studies have shown that cannulation success is raised with fewer attempts and the time to effective cannulation is reduced.
  • Furthermore, the use of ultrasonography is linked to a lower risk of pneumothorax, hematoma, and vascular puncture. However, there is a scarcity of information on the use of an ultrasound-guided subclavian approach.
  • It takes a lot of practice to get the correct way of ultrasound-guided subclavian entry.

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Medically Reviewed on 4/5/2022
References
Image Source: iStock Images

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Patrick SP, Tijunelis MA, Johnson S, Herbert ME. Supraclavicular subclavian vein catheterization: the forgotten central line. West J Emerg Med. 2009;10(2):110-114. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2691520/

Braner DAV, Lai S, Eman S, Tegtmeyer K. Central Venous Catheterization — Subclavian Vein. N Engl J Med. 2007; 357:e26. https://www.nejm.org/doi/full/10.1056/nejmvcm074357

Choo SW, Choo IW, Do YS, et al. Placement of Central Venous Access via Subclavian Vein under Fluoroscopic Guidance with Intravenous Contrast Injection. J Korean Radiol Soc. 1997 Jan;36(1):51-54. https://jksronline.org/pdf/10.3348/jkrs.1997.36.1.51